People using this deserve that their code breaks. Absolutely ridiculous.
Neither this, nor the leftpad thing, nor this is-even “package” are things I would even think about for a second before just writing it on my own. I wouldn’t even consider those features (let alone packages to depend my code on!) but basic programming.
I mean, does any language implement is_odd() natively? Doesn't everyone implement modulus and pretty much assumes that you remember modulus from elementary and can infer that even numbers are those where x % 2 == 0.
Let’s call the number variable just x, you then have literal math (Euclidean division) if you ignore === instead of = for equals.
x % 2 === 0
This can’t get better or more native than “just math”. This is the whole code you need to detect if a number is even. I wouldn’t even call it “code”.
If you remove whitespaces and ignore the type you end up with x%2==0 which is 6 characters long and a fully valid if clause. No magic involved, no abstraction, no weird function calls on integers …
I see that in modern JS this type of coding is a trend, but you can’t tell me you want to replace 6 characters with an own module or a package. :)
No, I want that in the std lib. Yes, it would just call x % 2 == 0 underneath. But the advantage is readability. I'm in principle aware that x % 2 == 0 is true when the number is even, but I need it seldomly enough that I do still need to think about it for a second before I know for sure. I don't need to think about x.is_even(). And the readability is what I want natively, i.e. in the std lib.
It being in the std lib would also sidestep your concerns about security or the function call having unknown side effects.